Waste Technology Section

Overview of Disposal Options

The diversity of radioactive waste to be dealt with, as well as the range of disposal facility designs and environmental settings available, has resulted in the development of several alternative disposal concepts. Many concepts have been put into practice and radioactive waste disposal has been safely practiced around the world since the middle of the last century.

Consequently, a large number of waste disposal facilities have been constructed and are being operated today for all waste categories; the only exception relates to the completion and operation of disposal facilities for high level waste and spent nuclear fuel (when declared as waste). However, the viability of disposing of this type of waste in deep geological formations has been provided through many years of research and demonstration, including experiments carried out in dedicated underground research laboratories.

The selection of the design and number of disposal facilities required in a country depends on many aspects, such as:

National waste and spent fuel management policy and strategy;

Waste inventories;

plans for nuclear energy exploitation; and

Extent of the national nuclear programme.

The currently applied disposal options are indicated with respect to the 2009 IAEA waste classification system as follows:

Very short lived waste is stored for decay and then cleared for disposal as non-radioactive waste.

Very low level waste can be directed into surface trenches utilising a limited engineered barrier system. Such facilities have been built in Sweden (at each nuclear power plant), France and Spain (see the Fig. 1). In many other countries this waste is disposed of together with low level waste.

Low level waste is typically put into near surface engineered facilities, such as those operating in France, Spain, Czech Republic and Slovakia (Fig. 2).

Fig. 2: El-Cabril disposal facility, Spain. (Photo credit: ENRESA)

In arid areas like South Africa, USA and Iran (Fig. 3) the low level waste is disposed of in open trenches with limited or no isolation layers, as the capping of trenches prevents water ingress into the disposal spaces and the natural environment is suitable for such disposal.

Some countries, such as Sweden, Finland, Norway, Czech Republic, Hungary and Korea (Fig. 4), have built or are building subsurface engineered facilities for low level waste, whereas Germany, Switzerland and Canada (Fig. 5) are developing deep geological facilities for this waste category.

For the disposal of transuranic waste arising from the US defense program, broadly corresponding to intermediate level waste in the new IAEA Waste Classification scheme (2009), the WIPP facility in the USA is an example of an operational deep geological repository(see Fig. 6). It is intended that long-lived intermediate level waste will also be disposed of in deep geological subsurface facilities planned or being constructed in Japan, Germany, UK, Canada and other countries. These include facilities that are primarily designated for high level waste disposal, but with appropriate demonstrations of safety and regulatory permissions, the co-disposal of intermediate level waste may be acceptable as well (Switzerland, France).

High level waste (and spent nuclear fuel) must be disposed of in a deep geologic formation. Intensive research performed in underground laboratories (see Fig. 7) has demonstrated the viability of this approach for salt (Germany, USA), granite (Switzerland, Canada, Sweden, Japan), plastic clay (Belgium) and clay stone (Switzerland, France) host formations. The first repositories are anticipated to become operational in the early twenties (Finland, Sweden and France). Some other countries have initiated siting and investigation programmes (Germany, Switzerland, Czech Republic, Slovakia, Hungary, Russia) while others are planning for the geological disposal of high level waste and spent nuclear fuel.

Disused sealed radioactive sources (DSRS) exist in practically all Member States. DSRS may exhibit high levels of activity even after they are no longer in use. After their productive lifetime they are stored and, in some cases, repatriated to the country of origin. However, most DSRS must be managed in the country where they were used. For Member States where financial or human resources are limited or where the necessary infrastructure to safely manage DSRS in the long-term is inadequate, a specific design for a borehole disposal facility has been developed by the IAEA as a simple, safe, secure, economic and practical final management solution

The IAEA concept for Borehole Disposal of DSRS (BOSS) consists of:

Source identification;

Conditioning for disposal;

Storage until a disposal facility is available; and finally

Emplacement in a borehole specially situated and constructed for the purpose of disposal.

Facility siting activities have been initiated in Ghana, Philippines, Malaysia and Iran and several other countries are also considering adopting the concept. Although the borehole disposal concept has been tailored specifically for small waste management programmes dealing only with DSRS, its viability has also been considered for use in larger programmes.